I ran into some issues while running 'bundle install' on a production server. This occured when bundler hit the 'sqlite3' gem.
Polymorphic Associations are a method for dealing with database models that have some sort of logical relationship. One model can belong to many other models on a single association. What this means is that a model can have many one-to-one relationships with other models. Lets see if an example explains this a bit better.